In recent years, e-mail which sends and receives character information through a network is becoming widespread with the spread of computers and increasing networking of information. E-mail allows files in various forms to be attached in addition to mail text which is character information. For example, Internet FAX (hereinafter, abbreviated as “IFAX”) which sends and receives an image with a TIFF (Tag Image File Format) file attached as an attached file is becoming widespread.
IFAX is a technology for communicating among devices which can convert an image read using a scanner into a TIFF format, transmit it from a transmitter, reproduce the TIFF format image from the data received by the receiver and print the image.
When an e-mail is sent with a file of a big data size attached thereto here, the delivery of the e-mail is delayed because of a load on the processing by a mail server, and when the load is further aggravated, there may be even a case where the whole e-mail delivery service is stopped. Therefore, the mail server is generally often set so as not to receive any e-mail exceeding a predetermined data size. When an e-mail with an image of a big data size attached is sent to the mail server with such a setting from IFAX, delivery errors may occur in the mail server.
For example, when an e-mail is sent with an image attached thereto using a PC, it is comparatively easy to confirm the data size of the attached image. However, in case of IFAX, it is not until the image is scanned and transmitted that the data size of the image is known and it is difficult to predict the data size and there is a high possibility that the above described delivery errors may frequently occur. Therefore, there is a proposal of a technology about an Internet facsimile apparatus which divides image information corresponding to a plurality of pages in page units and transmits those pages (Japanese Patent Laid-Open No. 2000-32202).
Furthermore, there is a proposal of a technology which performs printing/transfer processing in page order of original image information when e-mail data transmitted with image information of a plurality of pages divided in page units is received (Japanese Patent Laid-Open No. 2004-236005). Moreover, MIME Content-Type defines a method of dividing one piece of e-mail data into a plurality of e-mails or combining a plurality of divided pieces of e-mail data into one using an identifier called “message/partial” (RFC 2045, RFC 2046).
Reception of e-mail obtained by dividing one piece of e-mail data into a plurality of e-mails (hereinafter, referred to as “split mail”) has the following problem.
First, when data of a plurality of pages is divided in page units, each piece of data is attached to e-mail and transmitted, even if they are transmitted in order of page numbers, the data is passed through a mail server on the way, and therefore the order of page numbers is not guaranteed on the receiving side. Moreover, part of the e-mail to which a split page is attached may not reach the receiving side.
With regard to such a problem, Japanese Patent Laid-Open No. 2004-236005 discloses that when some of a plurality of split mails do not reach, the split mails are deleted when a predetermined time elapses after some split mails are received.
However, according to the method of waiting for a predetermined time to receive all split mails, if the predetermined time is too short, processing (printing processing, deletion processing and so on) of the split mails which have already been received may be carried out before receiving some split mails due to a delay in the processing by the server. On the other hand, if the predetermined time is too long, there is a problem that the processing of the split mails which have already been received may be delayed when some of the split mails do not reach.
Thus, instead of waiting for a predetermined time until all split mails are received, the processing of the split mails (printing processing, deletion processing and so on) may be performed through operation by an IFAX user (operator) who receives the split mails.
However, since, for example, some of the plurality of split mails are not received, when the split mails are deleted, it is complicated to perform processing (deletion or the like) on each of the plurality of split mails. For example, when the user is instructed to select split mails on an operation panel of IFAX and delete those mails, the user needs to select a plurality of split mails explicitly and delete them. Furthermore, according to the method described in Patent Document 2, a decision as to whether or not to delete split mails must be made for each split mail and the decision process produces a processing load.